προίημι

From LSJ

ὁ γὰρ μανθάνων κιθαρίζειν κιθαρίζων μανθάνει κιθαρίζειν → he who is learning the harp, learns the harp by harping

Source

English (Slater)

προίημι
   a send out προῆκαν υἱὸν ἀθάνατοι οἱ πάλιν (O. 1.65)
   b allow c. dat. & inf. “καί τοι μοναρχεῖν καὶ βασιλευέμεν ὄμνυμι προήσειν” (P. 4.166)

Middle Liddell

3 pres. προΐει as if from προΐω 3 opt. προΐοι Attic imperf. προΐειν Attic imperf -εις Attic imperf -ει fut. προήσω aor1 προῆκα epic προέηκα 3rd pl. aor2 πρόεσαν opt. προεῖεν imperat. πρόες 3rd sg. προέτω inf. προέμεν for προεῖναι Mid., aor1 προηκάμην 3rd pl. aor2 opt. πρόοιντο πρόειντο Pass., perf. προεῖμαι 3rd sg. plup. προεῖτο
I. to send before, send on or forward, Hom.: also, to send something to another, ἀγγελίας, φήμην Od.:—Hom. often with an inf. added; αἰετὼ προέηκα πέτεσθαι, οὖρον προέηκεν ἀῆναι Od.
2. to send away, dismiss, let go, Il.; τήνδε θεῷ πρόες let her go to the god, i. e. in reverence to him, Il.
3. to let loose, let fall, esp. thoughtlessly, ἔπος προέηκε let drop a word, Od.; πηδάλιον ἐκ χειρῶν προέηκε he let the helm slip from his hands, Od.; δάκρυα προῆκεν Eur.
4. of missiles, to send forth, shoot or dart forth, Hom.
5. of a river, ὕδωρ προΐει ἐς Πηνειόν it pours its water into the Peneius, Il.
6. πρ. τινί ποιεῖν τι to allow one to do, Pind.
II. to give up, deliver over, betray one to his enemy, Hdt., Thuc.: —Pass. to be given or thrown away, εἰ προεῖτο ταῦτα Dem.
2. ἐπὶ τὸ αὐτίκα ἡδὺ πρ. αὑτόν to give up or devote oneself to present delights, Xen.
B. Mid. to send forward from oneself, drive forward, Xen.:—of sounds, to utter, Aeschin., etc.
II. to give up, let go: to give up to the enemy, Thuc., etc.; πρ. σφᾶς αὑτούς gave themselves up as lost, Thuc.
2. to desert, abandon, Thuc.; οὐδαμῆ προΐεντο ἑαυτούς did not lose themselves (i. e. take bribes), Dem.
3. to give away, give freely, Thuc., etc.; προέσθαι ἀπὸ τῶν ἰδίων Dem.
4. to throw off one's clothes, Dem.: and, in bad sense, to throw away, τὸν καιρόν Dem.; τὰ πατρῷα Aeschin.: absol. to be lavish, Arist.
5. a second predicate is sometimes added, ἡμᾶς προέσθαι ἀδικουμένους to suffer us to be wronged, Thuc.; προέμενοι αὐτοὺς ἀπολέσθαι Xen.; πρ. τινὶ ὑμᾶς ἐξαπατῆσαι Dem.
6. to suffer to escape, Polyb.
7. rarely in good sense, to give over to one, confide to one's care, Xen.
III. to neglect, disregard, Arist.:— absol. to neglect all advice, to be reckless, Dem.

Lexicon Thucydideum

permittere, to permit, allow, 8.32.3,
MED. deserere, to abandon, desert, 1.36.3, 1.120.2, 2.73.3. 3.14.1. 6.31.2, 6.78.3.
in potestatem tradere, to deliver into one's power, 1.44.2, 1.71.4,
proiicere, to throw forth, cast out, 2.51.4,
largiri, to bestow, grant, 2.43.1.